Process of developing photographic plates or the like in open daylight.



iJNiTEp STATES Patented April 11, 1905.

ATENT FFICE,

JUHANN NICOLAUS LUDWlG, OF MAQINZ, GERWANY.

PROCESS OF DEVELOPING PHOTOGRAPHIC PLATES OR THE LIKE IN OPEN DAYLIGHT.

SPECIFICATION forming part of Letters Patent No. 787,103, dated April11, 1905.

Application filed February 17, 1902. Serial No. 94,572.

To (b// 11w]! 0/11 if IIIM/f/ con/(term:

Be it known that I, JOHANN NIooLAUs LUD- WIN, a subject of the (iermanEmperor, and a resident of Mainz, (-iermany, have invented certain newand useful improvements in Processes of Developing Photographic Platesor the Like in Open l):1 \lig"lit, of which the following is aIspecilication.

The present invention relates to an improved process wherebyphotographic plates may be removed directly from a camera orplate-holder and developed in daylight, thus avoiding the necessity andinconvenience of the operator entering a dark room to transfer theplates to the developing solution and remaining there until thedevelopment is wholly or partially accoi'nplished.

l have found that certain coloring-matters have the property of coloringor coating the sensitive surface of photographic plates and iilms so asto render them insensitive to actinic rays of light and that aphotographic plate or tilm after it has been exposed in a camera mayhave this coating applied thereto, so that it may be transferred to thedeveloper in daylight. Not all coloring materials, of course, arecapable of producing this result, the most suitable of course beingthose that will retain the greatest quantity of actinic rays.

A coloring material suitable for the purpose is that known as scarletsatlron 31%; but of course any other coloring material capable ofproducing the desired result may be used.

in proceeding according to my invention, for example, after exposing theplate in an ordinary camera l apply the liquid to the plate before it isremoved. \Vhen an ordinary metallic plate-holder is used, the liquid maybe poured into the plate-holder through a small opening, so as tothoroughly coat the plate, and it may then be withdrawn from theplateholder in ordinary daylight and developed in the usual way.

\Vhen a magazine plate or lilm camera is used of that nature in whichthe plates or lilms after exposure drop or pass into a separate part ofthecamera as, for instance, the bottom of the camera the coating liquidmay be applied to the plates or lilms while in such part.

1 am aware that it has been heretofore proposed to apply a coloringsolution to the developer, so that after the plates have becomepartially developed the process of development may be iinished inordinary daylight, and I therefore do not claim so broadly as to includesuch process.

Having now fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

The process of treating photographic plates or films which consists inlirst treating the exposed negative while still in the receptacle inwhich it has been exposed with a coloring material adapted to absorbactinic light, and subsequently developing the coated plate in anordinary developer by daylight, substantially as described.

In testimony whereof I have hereunto set my hand in presence of twowitnesses.

.lOllAXX NlUtlhAUS liUllWlh'.

\Vitnesses:

\VAL'ruu HAUsiNo, \VALTER Sounuaxx.

